Articles including anticondensation coatings and/or methods of making the same

ABSTRACT

Certain example embodiments of this invention relate to articles including anticondensation coatings that are exposed to an external environment, and/or methods of making the same. In certain example embodiments, the anticondensation coatings may be survivable in an outside environment. The coatings also may have a sufficiently low sheet resistance and hemispherical emissivity such that the glass surface is more likely to retain heat from the interior area, thereby reducing (and sometimes completely eliminating) the presence condensation thereon. The articles of certain example embodiments may be, for example, skylights, vehicle windows or windshields, IG units, VIG units, refrigerator/freezer doors, and/or the like.

FIELD OF THE INVENTION

Certain example embodiments of this invention relate to articlesincluding anticondensation coatings, and/or methods of making the same.More particularly, certain example embodiments of this invention relateto articles including anticondensation coatings that are exposed to anexternal environment, and/or methods of making the same. In certainexample embodiments, the anticondensation coatings may be survivable inan outside environment and also may have a low hemispherical emissivitysuch that the glass surface is more likely to retain heat from theinterior area, thereby reducing (and sometimes completely eliminating)the presence condensation thereon. The articles of certain exampleembodiments may be, for example, skylights, vehicle windows orwindshields, IG units, VIG units, refrigerator/freezer doors, and/or thelike.

BACKGROUND AND SUMMARY OF EXAMPLE EMBODIMENTS OF THE INVENTION

Moisture is known to condense on skylights, refrigerator/freezer doors,vehicle windows, and other glass products. Condensation buildup onskylights detracts from the aesthetic appeal of the lite. Similarly,condensation buildup on refrigerator/freezer doors in supermarkets orthe like sometimes makes it difficult for shoppers to quickly and easilypinpoint the products that they are looking for. And condensationbuildup on automobiles often is an annoyance in the morning, as a driveroftentimes must scrape frost or ice and/or actuate the vehicle'sdefroster and/or windshield wipers to make it safer to drive. Moistureand fog on the windshield oftentimes presents a similar annoyance,although they may also pose potentially more significant safety hazardsas a driver traverses hilly areas, as sudden temperature drops occur,etc.

Various anticondensation products have been developed over the years toaddress these and/or other concerns in a variety of applications. See,for example, U.S. Pat. Nos. 6,818,309; 6,606,833; 6,144,017; 6,052,965;4,910,088, the entire contents of each of which are hereby incorporatedherein by reference. As alluded to above, certain approaches use activeheating elements to reduce the buildup of condensation, for example, asin vehicle defrosters, actively heated refrigerator/freezer doors, etc.These active solutions unfortunately take time to work in the vehiclecontext and thus address the problem once it has occurred. In the caseof refrigerator/freezer doors, such active solutions may be expensiveand/or energy inefficient.

Some attempts have been made to incorporate a thin-film anticondensationcoating on a window. These attempts generally have involvedpyrolitically depositing a 4000-6000 angstrom thick fluorine-doped tinoxide (FTO) coating on the exterior surface (e.g., surface 1) of awindow such as, for example, a skylight. Although pyrolytic depositiontechniques are known to present “hard coatings,” the FTO unfortunatelyscratches fairly easily, changes color over time, and suffers from otherdisadvantages.

Thus, it will be appreciated there is a need in the art for articlesincluding improved thin-film anticondensation coatings, and/or methodsof making the same.

One aspect of certain example embodiments relates to anticondensationcoatings that are suitable for exposure to an external environment,and/or methods of making the same. The external environment in certainexample instances may be the outside and/or the inside of a vehicle orhouse (as opposed to, for example, a more protected area betweenadjacent substrates).

Another aspect of certain example embodiments relates toanticondensation coatings that have a low sheet resistance and a lowhemispherical emissivity such that the glass surface is more likely toretain heat from the interior area, thereby reducing (and sometimescompletely eliminating) the presence condensation thereon.

Still another aspect of certain example embodiments relates to coatedarticles having an anticondensation coating formed on an outer surfaceand one or more low-E coatings formed on one or more respective interiorsurfaces of the article. In certain example embodiments, theanticondensation coating may be thermally tempered (e.g., at atemperature of at least 580 degrees C. for at least about 2 minutes,more preferably at least about 5 minutes) or annealed (e.g., at atemperature lower than that required for tempering).

The articles of certain example embodiments may be, for example,skylights, vehicle windows or windshields, IG units, VIG units,refrigerator/freezer doors, and/or the like.

Certain example embodiments of this invention relate to a skylight.First and second substantially parallel, spaced apart glass substratesare provided. plurality of spacers are arranged to help maintain thefirst and second substrates in substantially parallel, spaced apartrelation to one another. An edge seal helps seal together the first andsecond substrates. An anticondensation coating is provided on anexterior surface of the first substrate exposed to an environmentexternal to the skylight. The anticondensation coating comprises thefollowing thin-film layers deposited in the following order moving awayfrom the first substrate: a silicon-inclusive barrier layer, a firstsilicon-inclusive contact layer, a layer comprising a transparentconductive oxide (TCO), a second silicon-inclusive contact layer, and alayer of zirconium oxide. The anticondensation coating has ahemispherical emissivity of less than less than 0.23 and a sheetresistance of less than 30 ohms/square.

According to certain example embodiments, a low-E coating is provided onsurface 2 and/or 3 of the skylight.

Certain example embodiments of this invention relate to a coated articlecomprising a coating supported by a substrate. The coating is ananticondensation coating comprising the following thin-film layersdeposited in the following order moving away from the first substrate: asilicon-inclusive barrier layer, a first silicon-inclusive contactlayer, a layer comprising a transparent conductive oxide (TCO), a secondsilicon-inclusive contact layer, and a layer of zirconium oxide. Theanticondensation coating is disposed on an exterior surface of thesubstrate such that the anticondensation coating is exposed to anexternal environment. The anticondensation coating has a hemisphericalemissivity of less than less than 0.23 and a sheet resistance of lessthan 30 ohms/square.

According to certain example embodiments, the external environment isthe inside of a house or vehicle. According to certain exampleembodiments, the external environment is the outside environment.According to certain example embodiments, a low-E coating is provided onthe substrate opposite the anticondensation coating.

In certain example embodiments, the coated article may be built into askylight, window, insulating glass (IG) window, vacuum insulating glass(VIG) window, refrigerator/freezer door, and/or vehicle window orwindshield. The anticondensation coating may be provided on surface 1and/or surface 4 of an IG or VIG unit, for example.

The features, aspects, advantages, and example embodiments describedherein may be combined to realize yet further embodiments.

BRIEF DESCRIPTION OF THE DRAWINGS

These and other features and advantages may be better and morecompletely understood by reference to the following detailed descriptionof exemplary illustrative embodiments in conjunction with the drawings,of which:

FIG. 1 is a coated article including an anticondensation coating inaccordance with an example embodiment;

FIG. 2 is an insulating glass unit including an anticondensation coatingdisposed on an outermost surface exposed to the exterior atmosphere inaccordance with an example embodiment;

FIG. 3 is an insulating glass unit including an anticondensation coatingdisposed on an innermost surface exposed to the interior environment inaccordance with an example embodiment;

FIG. 4 is an insulating glass unit including anticondensation coatingsdisposed on outermost and innermost surfaces of the insulating glassunit in accordance with an example embodiment; and

FIG. 5 is a graph illustrating the performance of an example embodiment,a current anticondensation product, and a bare glass substrate as thetemperature, humidity, and dew point change over an 18 hour time period.

DETAILED DESCRIPTION OF EXAMPLE EMBODIMENTS OF THE INVENTION

Certain example embodiments of this invention relate to thin-filmanticondensation coatings that are exposed to the environment. Suchcoatings have a low hemispherical emissivity in certain exampleembodiments, which helps the glass surface retain heat provided from theinterior side. For instance, in skylight and/or other building windowexample applications, the glass surface retains more heat from theinterior of the building. In vehicle example applications, thewindshield retains more heat from the interior of the vehicle. Thishelps reduce (and sometimes even prevent) the initial formation ofcondensation. As alluded to above, such anticondensation coatings may beprovided on a surface (or multiple surfaces) exposed to the environmentin certain example instances. As such, the anticondensation coatings ofcertain example embodiments may be robust so as to be able to survivesuch conditions.

FIG. 1 is a coated article including an anticondensation coating inaccordance with an example embodiment. The FIG. 1 example embodimentincludes a glass substrate 1 supporting a multilayer thin-filmanticondensation coating 3. The anticondensation coating 3 has a lowhemispherical emissivity. In certain example embodiments, thehemispherical emissivity is less than 0.25, more preferably less than0.23, still more preferably less than 0.2, and sometimes even less than1.0-1.5. This is achieved by providing a thin transparent conductiveoxide layer (TCO) 5 such that a suitably low sheet resistance isachieved. In the FIG. 1 example, the TCO 5 is indium tin oxide (ITO). Asheet resistance of the 10-30 ohms/square generally will be sufficientto achieve the desired hemispherical emissivity values. Certain exampleembodiments described herein provide a sheet resistance of 13-27ohms/square, with the example provided below providing a sheetresistance of 17 ohms/square. In certain example instances, it ispossible to select a TCO 5 such that the sheet resistance drops to aslow as about 5 ohms/square, although this low value is not need in allembodiments of this invention.

The TCO 5 is protected from the environment by a layer or zirconiumoxide 7. A silicon-inclusive barrier layer 11 may be provided betweenthe TCO5 and the substrate 1 also to help protect the TCO 5, e.g., fromsodium migration. In the FIG. 1 example, the silicon-inclusive barrierlayer 11 is silicon nitride, and the silicon nitride barrier layer 11 isprovided adjacent to a layer of titanium oxide 13. The silicon nitridebarrier layer 11 and the layer of titanium oxide 13 in the FIG. 1example help with the optics of the overall article. It will beappreciated that a low/high/low layer stack system also may be used toimprove the optics of the end product in certain example instances. Incertain example embodiments, the silicon nitride barrier layer 11 may beoxided, e.g., so that it is a layer of silicon oxynitride. In certainexample embodiments, a barrier layer comprising silicon nitride (e.g.,Si₃N₄ or other suitable stoichiometry) may replace the silicon-inclusivebarrier layer 11 and the titanium oxide layer 13 in the FIG. 1 example.

Additional silicon-inclusive layers 9 a and 9 b may sandwich the TCO 5.As shown in the FIG. 1 example, the upper silicon-inclusive layer 9 a isa layer of silicon nitride, whereas the lower silicon-inclusive layer 9b is a layer of silicon oxynitride. it will be appreciated that anysuitable combination of silicon with oxygen and/or nitrogen may be usedin different embodiments of this invention.

The following table provides example physical thicknesses and thicknessranges for the FIG. 1 example embodiment:

Example Thickness Range (nm) Example Thickness (nm) ZrOx 2-15 7 SiNx10-50  30 ITO 75-175 130 SiOxNy 10-50  35 TiOx 2-10 3.5 SiNx 10-20  13

As indicated above, other TCOs may be used in place of, or in additionto, ITO. For instance, certain example embodiments may incorporate anITO/Ag/ITO sandwich. Certain example embodiments, may incorporate zincoxide, aluminum-doped zinc oxide (AZO), p-type aluminum oxide, doped orun-doped Ag, FTO, and/or the like. When Ag is incorporated into thelayer stack system as a TCO, layers comprising Ni and/or Cr may beprovided directly adjacent (contacting) the Ag. In certain exampleembodiments, each layer in the layer stack system may besputter-deposited. In certain example embodiments, one or more layersmay be deposited using a different technique. For instance, when FTO isincorporated as the TCO 5, it may be pyrolytically deposited (e.g.,using combustion vapor deposition or CVD).

In certain example embodiments, layer of diamond-like carbon (DLC) maybe provided directly over and contacting the zirconium oxide. This mayhelp to create a more survivable, hydrophilic-like coating in certainexample instances. Hydrophilic coatings generally involve a contactangle of less than or equal to 10 degrees. Sputter-deposited zirconiumoxide tends to have a contact angle of less than about 20 degrees.However, forming DLC on top of the DLC on top of the zirconium oxidehelps with its wettability and creates a harder layer. When tempered,for example, a zirconium oxide/DLC layer stack reaches a contact angleof less than or equal to about 15 degrees. Thus, a survivable,hydrophilic-like coating may be achieved. It is noted that this layermay be created by providing a layer of zirconium nitride followed by alayer of DLC which, upon tempering, will produce a layer of zirconiumoxide followed by a layer of DLC. See, for example, application Ser. No.12/320,664, which describes a heat treatable coated article includingDLC and/or zirconium in its coating. The entire contents of thisapplication are hereby incorporated herein by reference.

In addition or in the alternative, in certain example embodiments, athin hydrophilic and/or photocatalytic coating may be provided over thezirconium oxide. Such a layer may comprise anatase TiO₂, BiO, BiZr,BiSn, SnO, and/or any other suitable material. Such a layer also mayhelp with wettability and/or provide self-cleaning properties to thearticle.

In certain example embodiments, the zirconium oxide protective layer 7may be replaced with aluminum oxide and/or aluminum oxide.

Although not shown in the FIG. 1 example, a silver-based low-E coatingmay be provided on the glass substrate opposite the anticondensationcoating 3. For example, the silver-based low-E coating may be any one ofthe low-E coatings described in application Ser. Nos. 12/385,234;12/385,802; 12/461,792; 12/591,611; and 12/654,594, the entire contentsof which are hereby incorporated herein by reference. Of course, otherlow-E coatings commercially available from the assignee of the instantinvention and/or other low-E coatings also may be used in connectionwith different embodiments of this invention. When the coated article istempered, it may be run through a tempering furnace “face down.” Inother words, when the coated article is tempered, the anticondensationcoating may face the rollers.

In certain example embodiments, the visible transmission may be highwhen an anticondensation coating is applied. For example, in certainexample embodiments, the visible transmission preferably will be atleast about 50%, more preferably at least about 60%, still morepreferably at least about 65%. In certain example embodiments, thevisible transmission may be 70%, 80%, or even higher.

The coated article shown in FIG. 1 may be incorporated into a insulatingglass (IG) unit. For example, FIG. 2 is an insulating glass unitincluding an anticondensation coating disposed on an outermost surfaceexposed to the exterior atmosphere in accordance with an exampleembodiment. The IG unit in the FIG. 2 example includes first and secondsubstantially parallel spaced apart glass substrates 1 and 21. Thesesubstrates define a space or gap 22 therebetwen. The first and secondsubstrates 1 and 21 are sealed using an edge seal 23, and a plurality ofpillars 25 help maintain the distance between the first and secondsubstrates 1 and 21. The first substrate 1 supports the anticondensationcoating 3. As will be appreciated from the FIG. 2 example embodiment,the anticondensation coating 3 is exposed to the exterior environment.This is a departure from common practices, where low-E coatingsgenerally are protected from the external environment. The FIG. 2arrangement becomes possible because of the durability of theanticondensation coating 3.

Although not shown in FIG. 2, similar to as described above, a low-Ecoating (e.g., a silver-based low-E coating) may be provided on aninterior surface of one of the first and second substrates 1 and 21. Inother words, although not shown in FIG. 2, a low-E coating may beprovided on surface 2 or surface 3 of the IG unit shown in FIG. 2.

When the FIG. 2 example embodiment is provided in connection with askylight application, for example, the outer substrate 1 may be temperedand the inner substrate 21 may be laminated, e.g., for safety purposes.This may be true of other IG unit products, as well, depending on thedesired application. In addition, it will be appreciated that the IGunit structure shown in the FIG. 2 example may be used in connectionwith generally vertical and generally horizontal applications. In otherwords, the IG unit structure shown in the FIG. 2 example may be used inrefrigerator/freezer doors that are either generally upright orgenerally horizontal.

In certain example embodiments, the space or gap 22 between the firstand second substrates 1 and 21 may be evacuated and/or filed with aninert gas (such as argon, for example), and the edge seal 23 may providean hermetic seal, e.g., in forming a vacuum insulated glass (VIG) unit.

FIG. 2 shows an IG unit having two glass substrates. However, theexample anticondensation coatings described herein may be used inconnection with products that contain first, second, and thirdsubstantially parallel and spaced apart glass substrates (also sometimesreferred to as “triple-glaze” products). The anticondensation coatingmay be disposed on surface 1 (the outermost surface exposed to theenvironment), and low-E coatings may be disposed on one or more interiorsurfaces (surfaces other than surface 1 and surface 6). For example, theanticondensation coating may be disposed on surface 1, and low-Ecoatings may be disposed on surfaces 2 and 5, 3 and 5, etc., indifferent embodiments of this invention. Such triple-glaze products maybe IG units containing three lites or substrates, trip VIG unitscontaining three lites or substrates, etc., in different embodiments ofthis invention.

As indicated above, certain example embodiments may be used inconnection with vehicle windshields, windows, mirrors, and/or the like.The hemispherical emissivity of the exterior glass surfaces of a vehicletypically is greater than about 0.84. However, by reducing thehemispherical emissivity to the above-identified (and/or other) ranges,the glass surface may retain more heat provided by the interior of thevehicle. This, in turn, may result in reduced or eliminated condensationbuildup on the lite surface when a moving vehicle goes from colder towarmer climate (e.g., in hilly areas), reduced or eliminatedcondensation and/or frost buildup on the lite when parked and left overnight, etc. The anticondensation coating in vehicle applications may beprovided on the side of the glass that is exterior to the vehicle cabin.

The zirconium oxide topcoat is advantageous for vehicle windowapplications, as it has a comparatively low coefficient of friction.More particularly, this lower coefficient of friction facilitates theupward and downward movement of windows.

Certain example embodiments may be used in connection with any suitablevehicle including, for example, automobiles; trucks; trains; boats,ships and other vessels; airplanes; tractors and other work equipment;etc. In vehicle mirror applications, the optics of the coating may betune such that a “double reflection” does not occur.

The inventors of the instant application have also realized that theanticondensation coating of certain example embodiments may be used tohelp meet the so-called “0.30/0.30 standard.” Briefly, the 0.30/0.30standard refers to a U-value of less than or equal to 0.30 and a solarheat gain coefficient (SHGC) of less than or equal to 0.30. Currentlegislation in the U.S. would give a tax credit for investing inwindows, skylights, doors, etc., that meet these criteria.

FIG. 3 is an insulating glass unit including an anticondensation coatingdisposed on an innermost surface exposed to the interior environment inaccordance with an example embodiment. The FIG. 3 example embodiment issimilar to the FIG. 2 example embodiment, except that the FIG. 3 exampleembodiment has the anticondensation coating 3 located on surface 4,which is the exterior surface of the inner glass substrate 1 that isexposed to the building interior rather than the outside environment.

In certain example embodiments, the inner substrate 1 may be annealed(rather than tempered). The anticondensation coating may remain the sameor substantially the same as between the FIG. 2 and FIG. 3 exampleembodiments, although the modifications described above in connectionwith FIGS. 1 and 2 also may be made in connection with an embodimentlike FIG. 3. One change that might be made is increasing the thicknessof the ITO to achieve the desired U-value performance. In such caseswhere the ITO is thickened, the thicknesses of the other layers may alsobe adjusted so that the desired optical properties are achieved.Additional layers also may be added to achieve the desired opticalproperties. The other structural elements remain the same as betweenFIGS. 2 and 3, and similar modifications may be made thereto.

When the anticondensation coating 3 is disposed on surface 4 as shown inFIG. 3, the U-value has been determined to be 0.29. When an additionallow-E coating is provided on surface 2 of the IG unit, the U-value hasbeen found to drop to 0.23. Certain example embodiments also may providea SHGC less than or equal to 0.30, thereby helping meet the 0.30/0.30standard.

In products with low U-values (e.g., IG or VIG units with theanticondensation coating on surface 4, two- and three-lite VIG units,etc.), condensation can become a problem, e.g., as the glass is notheated because of the low-emissivity coatings. One solution to thischallenge is presented in FIG. 4, which is an insulating glass unitincluding anticondensation coatings disposed on outer most and innermostsurfaces of the insulating glass unit in accordance with an exampleembodiment. In the FIG. 4 example, first and second substrates 1 a and 1b are provided. First and second anticondensation coatings 3 a and 3 bare provided on surfaces 1 and 4, respectively. In certain exampleembodiments, additional low-E coatings also may be provided on one orboth of the inner surfaces (surfaces 2 and/or 3). In this way, it ispossible to provide a product that exhibits U-value reduction andanticondensation behaviors.

FIG. 5 is a graph illustrating the performance of an example embodiment,a current anticondensation product, and a bare glass substrate as thetemperature, humidity, and dew point change over an 18 hour time period.The images in FIG. 5 each have a “crisscross” pattern printed thereon tohelp demonstrate the presence or absence of condensation. As can be seenfrom FIG. 5, there is virtually no condensation formed on those samplesthat were produced in accordance with an example embodiment. Bycontrast, the comparative example, which includes pyrolyticallydeposited FTO, shows some condensation being formed in the firstobserved period, with the level of condensation greatly increasingthrough the second and third observed periods, and abating slightly bythe fourth observed period. Indeed, the “crisscross” pattern issignificantly blurry at the second observed period and barely visibleduring the third. The uncoated glass sample shows significantcondensation during all observed periods. The “crisscross” pattern inthe second and third observed periods cannot be seen. The FIG. 5 examplethus demonstrates that the example embodiments described herein providesuperior performance when compared to the current comparative exampleand uncoated glass.

“Peripheral” and “edge” seals herein do not mean that the seals arelocated at the absolute periphery or edge of the unit, but instead meanthat the seal is at least partially located at or near (e.g., withinabout two inches) an edge of at least one substrate of the unit.Likewise, “edge” as used herein is not limited to the absolute edge of aglass substrate but also may include an area at or near (e.g., withinabout two inches) of an absolute edge of the substrate(s).

As used herein, the terms “on,” “supported by,” and the like should notbe interpreted to mean that two elements are directly adjacent to oneanother unless explicitly stated. In other words, a first layer may besaid to be “on” or “supported by” a second layer, even if there are oneor more layers therebetween.

While the invention has been described in connection with what ispresently considered to be the most practical and preferred embodiment,it is to be understood that the invention is not to be limited to thedisclosed embodiment, but on the contrary, is intended to cover variousmodifications and equivalent arrangements included within the spirit andscope of the appended claims.

1-28. (canceled)
 29. A coated article comprising: a coating supported bya glass substrate, wherein: the coating comprising the followingthin-film layers moving away from the glass substrate: a layercomprising silicon oxynitride, a transparent conductive layer comprisingindium tin oxide, a silicon-inclusive contact layer, wherein the coatingis disposed on an exterior surface of the glass substrate such that thecoating is to be exposed to an external environment, and the coating hasa hemispherical emissivity of less than 0.23 and a sheet resistance ofless than 30 ohms/square.
 30. The coated article of claim 29, whereinthe silicon-inclusive contact layer comprises silicon nitride.